![]() ![]() Fillers were added in two concentrations: 5 and 10 pph on dry starch. Moreover, two selected fillers were added: mineral sodium montmorillonite (M) and organic microcrystalline cellulose (C) to investigate their influence on TPS/DES materials. In this work, ternary DES UGS is used for starch processing via extrusion for the first time. In the previous work, we confirmed that DES based on urea, glycerol, and sorbitol (UGS) effectively plasticizes starch via thermocompression. In comparison with ILs, DES are easy-to-prepare media from “greener” (often from natural sources) and cheaper components obtained via mixing. DES are mixtures that exhibited phase transition temperatures at much lower temperature that their components. Due to the high cost of ILs and often non-green character, deep eutectic solvents are used as more eco-friendly tailorable, alternative media not only for starch treatment (e.g., plasticizing, dissolution) but also for polysaccharides processing such as their extraction, biomass pretreatment (e.g., delignification, fractionization, and separation). In the last two decades, interest in ionic liquids (ILs) as polysaccharide processing media rapidly increased. The most common starch plasticizers are glycerol (G) or other higher polyalcohols (sorbitol, maltitol), amides, sugars or carboxylic acids (in a smaller amount, they can also act as crosslinkers). Starch plasticizers disrupt H-bonding between polysaccharide chains and form new ones with OH groups of anhydroglucosidic units of the polymer. Due to native starch having a glass transition close to its degradation temperature, it needs a special additive to facilitate its modification. The modification via extrusion is solventless (water, more often in form as starch moisture, acts as a co-plasticizer), does not require water evaporation from casted materials and allows processing the material on a large scale in a short time, which is crucial issue from the industrial point of view. The TPS materials can be obtained e.g., via gelatinization of starch in aqueous media casting and evaporation of water or via extrusion. Starch plasticizers are low molecular polar compounds that enable the polysaccharide processing into more amorphous “plastic-like” materials called thermoplastic starch (TPS). Moreover, a cone calorimetry analysis of the TPS materials revealed that they showed better fire-retardant properties than TPS plasticized with a conventional plasticizer (glycerol). However, montmorillonite addition exhibited a higher impact than microcrystalline cellulose. The introduction of the two types of fillers resulted in higher tensile strength and better barrier properties of the composite TPS films. An investigation of the behavior in water (swelling and dissolution degree) and water vapor transmission rate of the films was determined. The ternary DES effectively plasticized the polysaccharide leading to a highly amorphous structure of the TPS (confirmed via mechanical tests, DMTA and XRD analyses). ![]() Then, the physicochemical properties of the TPS films were examined. Films were prepared via twin-screw extrusion and thermocompression of the extrudates. Potato starch was plasticized with ternary DES: urea:glycerol:sorbitol and modified with the selected fillers: microcrystalline cellulose and sodium montmorillonite. The aim of the study was to prepare and characterize composite materials based on thermoplastic starch (TPS)/deep eutectic solvent (DES). ![]()
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